Error Handling Programming Guide Pdf
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describe how to deal with NSError objects returned from framework methods, how to display error messages using error objects, how to error handling in programming languages create error objects, and how to implement methods that return
Programming Error Handling Best Practices
error objects by reference. Handling Error Objects Returned From MethodsMany methods of the Cocoa and Cocoa
C Programming Error Handling
Touch classes include as their last parameter a direct or indirect reference to an NSError object. In some Foundation and UIKit methods you find
R Programming Error Handling
NSError objects as arguments of delegation methods. The following declaration is from the UIKit framework’s UIWebViewDelegate protocol; a delegate would implement a method such as this to find out if an operation failed:- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error;Some methods of the Cocoa frameworks that you call include an indirect reference to an what is cocoa error -1 NSError object; these methods typically perform an operation such as creating a document, writing a file, or loading a URL. For example, the following method declaration is from the NSDocument class header file:- (BOOL)writeToURL:(NSURL *)absoluteURL ofType:(NSString *)typeName error:(NSError **)outError;If a method such as this encounters an error in its implementation, it directly returns NO to indicate failure and indirectly returns (if the client code requests it) an NSError object in the last parameter to describe the error.If you want to evaluate the error, declare an NSError object variable before calling a method such as writeToURL:ofType:error:. When you invoke the method, pass in a pointer to this variable. (If you are not interested in the error, just pass NULL.) If the method directly returns nil or NO, inspect the NSError object to determine the cause of the error or simply display an error alert. Listing 2-1 illustrates this approach.Listing 2-1Handling an NSError object returned
Top of chapter Character Set Source File Encoding Data Types Top of chapter Terms Number Atom Bit Strings and Binaries Reference Fun Port Identifier Pid Tuple Map List cocoa error -1 disk utility String Record Boolean Escape Sequences Type Conversions Pattern Matching Top of how to fix cocoa error -1 chapter Pattern Matching Modules Top of chapter Module Syntax Module Attributes Comments module_info/0 and module_info/1 functions Functions cocoa error 1 Top of chapter Function Declaration Syntax Function Evaluation Tail recursion Built-In Functions (BIFs) Types and Function Specifications Top of chapter The Erlang Type Language Types and their https://developer.apple.com/library/ios/documentation/Cocoa/conceptual/errorhandlingcocoa/CreateCustomizeNSError/CreateCustomizeNSError.html Syntax Type Declarations of User-Defined Types Type Information in Record Declarations Specifications for Functions Expressions Top of chapter Expression Evaluation Terms Variables Patterns Match Function Calls If Case Send Receive Term Comparisons Arithmetic Expressions Boolean Expressions Short-Circuit Expressions List Operations Map Expressions Bit Syntax Expressions Fun Expressions Catch and Throw Try Parenthesized Expressions Block Expressions List http://erlang.org/doc/reference_manual/errors.html Comprehensions Bit String Comprehensions Guard Sequences Operator Precedence Preprocessor Top of chapter File Inclusion Defining and Using Macros Predefined Macros Macros Overloading Flow Control in Macros -error() and -warning() directives Stringifying Macro Arguments Records Top of chapter Defining Records Creating Records Accessing Record Fields Updating Records Records in Guards Records in Patterns Nested Records Internal Representation of Records Errors and Error Handling Top of chapter Terminology Exceptions Handling of Run-time Errors in Erlang Exit Reasons Processes Top of chapter Processes Process Creation Registered Processes Process Termination Message Sending Links Error Handling Monitors Process Dictionary Distributed Erlang Top of chapter Distributed Erlang System Nodes Node Connections epmd Hidden Nodes C Nodes Security Distribution BIFs Distribution Command-Line Flags Distribution Modules Compilation and Code Loading Top of chapter Compilation Code Loading Code Replacement Running a Function When a Module is Loaded Ports and Port Drivers Top of chapter Ports Port Drivers Port BIFs 11 Errors and Error Handling 11.1 Terminology Errors can roughly be divided into four different types: Comp
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